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Research about Illinios

Source-linked reports with geographic coverage including Illinios.

7 recordsLinked to original sources
USGS2023

Estimating peak-flow quantiles for selected annual exceedance probabilities in Illinois

This report presents the methods, results, and applications of an updated flood-frequency study for the State of Illinois. This study, which uses data through September 2017, updates two previous studies that used data through 1999 and 2009, respectively. Flood-frequency estimates are used for a variety of land-use planning and infrastructure design purposes, including for the hydraulic design of bridges. The flood frequencies presented are the stream discharges (or quantiles) that are exceeded each year with a given probability, called the annual exceedance probability (AEP). Estimates are provided for eight AEPs: 0.5, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002. The basic data used are the annual maximum discharges (peak flows) at streamgages in and near Illinois and the measurable physical properties (basin characteristics) of the basins upstream from those streamgages. The logarithms of the peak flow records at qualifying streamgages were fit to the Pearson Type 3 distribution using federally recommended methods, providing one of the two primary products of the study, which is the set of peak-flow quantiles at the streamgages and their uncertainties. The other primary product is sets of equations, determined by least-squares regression, that relate the peak-flow quantiles and the basin characteristics. There is one set of equations for each of Illinois’ seven hydrologic regions, and, for each region, one equation for each AEP. These regional equations allow the estimation of peak-flow quantiles at ungaged locations throughout the state and their uncertainties. A set of illustrative example applications is provided, and tables of all results at all study streamgages and regions are provided in associated data releases. The study results are also being made available in a web application, StreamStats.

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USGS2003

Arsenic in Illinois ground water — Community and private supplies

Assessing the distribution of arsenic in ground water from community-water supplies, private supplies, or monitoring wells is part of the process of determining the risk of arsenic contamination of drinking water in Illinois. Lifestyle, genetic, and environmental factors make certain members of the population more susceptible to adverse health effects from repeated exposure to drinking water with high arsenic concentrations (Ryker, 2001). In addition, such factors may have geographic distribution patterns that complicate the analysis of the relation between arsenic in drinking water and health effects. For example, arsenic may not be the only constituent affecting the quality of drinking water in a region (Ryker, 2001); however, determining the extent and distribution of arsenic in ground water is a starting place to assess the potential risk for persons drinking from a community or private supply. Understanding the potential sources and pathways that mobilize arsenic in ground water is a necessary step in protecting the drinking-water supply in Illinois.

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USGS1986

Hydrogeology, ground-water flow, and tritium movement at low-level radioactive-waste disposal site near Sheffield, Illinois

Groundwater flow and tritium movement are described at and near a low-level radioactive waste disposal site near Sheffield, Illinois. Flow in the shallow aquifer is confined to three basins that ultimately drain into a stripmine lake. Most of the flow from the site is through a buried, pebbly sandfilled channel. Remaining flow is toward alluvium of an existing stream. Conceptual flow models for the two largest basins are used to improve definition of flow velocity and direction. Flow velocities range from about 25 to 2,500 ft/yr. Tritium was found in all three basins. The most extensive migration of tritium is coincident with buried channel. Tritium concentrations ranged from detection level to more than 300 nanocuries/L.

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USGS1984

Low-level radioactive-waste burial at the Palos Forest Preserve, Illinois: Geology and hydrology of the glacial drift, as related to the migration of tritium

A low-level radioactive-waste burial site is located in Palos Forest Preserve, about 22 kilometers southwest of Chicago, Illinois. Between 1943 and 1949 the site, named Plot M, was filled with radioactive waste from the first Argonne National Laboratory and from the University of Chicago Metallurgical Laboratory. Since 1973, tritium concentration levels up to 14 nanocuries per liter have been measured in water samples collected from a well 360 meters from the burial site. The U.S. Geological Survey is studying the geologic, hydrologic, and geochemical properties of the glacial drift and underlying bedrock at the Plot M site to determine the factors that control the movement of radionuclides. Test wells were drilled into the drift to collect water and core samples for laboratory analysis, to gather geologic and hydrologic data, and to conduct geophysical surveys. Plot M is located in drift that ranges in thickness from 25 to 45 meters. The drift is a stratified sequence of clay- and silt-rich sediments that contain thin, interstratified sand layers. The silt content of the drift increases with depth. The permeability of the drift, as indicated by field and laboratory hydraulic conductivity tests, ranges from 1.0 x 10 -6 to 1.0 ? 10 -8 centimeters per second. A tritium plume, the contaminated zone in the drift in which tritium concentration levels exceed 10 nanocuries per liter of water, extends horizontally northward from Plot M at least 50 meters and vertically downward to bedrock. The center of the plume, where tritium concentration levels are as high as 50,000 nanocuries per liter, is approximately 15 meters beneath the burial site. The size, shape, and 'bull's-eye' concentration pattern indicate that the plume is a single slug and that the site no longer releases tritium into the drift. The leading edge, or front, of the plume (the 10 nanocuries per liter boundary) left the burial site in either the late 1940's or the early 1950's and intersected the underlying bedrock surface before 1973. The calculated movement rate of the front is 6.3 x 10 -6 centimeters per second. Several key factors that control both the concentration level and the extent of migration of tritium in the drift at Plot M are 1. The limited amount of tritiated waste buried at Plot M. 2. The long period of time that has elapsed since the waste was buried (30-35 years) relative to the radioactive half-life of tritium (12.3 years). 3. The great thickness and low permeability of the glacial drift at the site.

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